This may seem an odd Notre Dame position group to include second in this series, when clarity should be abundant. That’s the thing — the uncertainty about the future of the linebacker corps is so prevalent it borders on certainty. It is very clear, moving forward there will be a lot of questions in the defense’s second unit, with up to three senior starters and captains leaving. Those questions are obvious, themselves. This is not going to be an instance of one or the other. Rather, it will be a “Who?” aimed at the entire positional meeting room.

WHERE NOTRE DAME WAS
Seniors and captains Nyles Morgan and Greer Martini gave defensive coordinator Mike Elko two established starters in the middle of his first Irish defense. It is a good position to be in when senior Drue Tranquill is the biggest question mark of a group.

Tranquill hardly was a doubt entering 2017, but his fit in the new role of rover was an unknown, albeit a promising unknown. To pull from his summary in the summer’s “Counting Down the Irish” series as the No. 7 entry, “Tranquill will now find himself in the middle of the defense. Already a vocal leader as a captain, this will give him a chance to also lead in action.”

WHERE NOTRE DAME IS
Morgan and Martini lived up to expectations, at least as much as they could while playing through injuries for much of the season. A shoulder issue plagued Morgan while a torn meniscus cost Martini the USC game.

Including this one of Heisman Trophy-finalist Bryce Love, Irish junior linebacker Te’von Coney made 99 tackles this season to lead the Notre Dame defense. (Photo by Ezra Shaw/Getty Images)

In his place that mid-October day and alongside both the senior captains throughout the year, junior Te’von Coney more than stepped forward. When looking to 2018, Coney’s emergence this year could set up for a star turn next fall.

Throughout much of the season, Coney and Tranquill were the best two linebackers on the field for Notre Dame. This was always expected to be a strong unit, and neither of its presumed leaders disappointed, which just goes to show how much Coney and Tranquill progressed in one season under Elko.

STATISTICALLY SPEAKING
The entire first paragraph of this section from last week’s defensive line entry is still applicable here: In 2016, Notre Dame allowed 182.4 rushing yards per game (No. 72 in the country), 378.8 total yards per game (No. 42) and 39.0 percent of third downs to be converted (No. 60). This season, the Irish have given up 153.2 rushing yards per game (No. 48), 366.7 total yards per game (No. 44) and successful third downs only 33.5 percent of the time (No. 28). Clearly, each metric improved in Elko’s first season with the Irish.

Clearly, senior captain and former safety Drue Tranquill put together the most-complete of the linebackers’ stat lines. (Getty Images)

COMING QUESTIONS
The first item to be settled is Tranquill’s decision between heading to the NFL Draft or returning for a fifth year. He will have an engineering degree and two surgically-repaired knees. Taking a shot at a professional career as soon as possible would be a decision no one could argue with.

However, Elko and Notre Dame head coach Brian Kelly would jump at the chance to welcome back Tranquill. He excelled in the rover position this year, not needing to worry about getting burned by speedy receivers running deep and instead focusing on running downhill and attacking the football.

Regardless of Tranquill’s choice, his heir apparent is not exactly, well, apparent. If needed in 2018, Bilal would seem the most logical candidate, but freshman Jeremiah Owusu-Koromoah was recruited with this exact assignment in mind. If he is not ready by September, then Elko and Kelly will hope Tranquill is around to man the position until Owusu-Koromoah is raring to go in 2019.

Beyond the rover, one most wonder who lines up alongside Coney. To be clear, Coney will start, he will presumably once again lead the Irish in tackles, and he will be the binding force of the front-seven. His 2017 arrival was that impressive.

Kelly’s coaching staff has been sure to pursue linebackers in the class of 2018, now with four commitments, including three consensus four-stars. It may be a position where depth is a noted asset, but this would be the most linebackers signed in one class since the 2014 class of … Martini, Morgan, Nile Sykes and Kolin Hill. Sykes did not reach his freshman year and Hill transferred to Texas Tech after his first season. Recruited as a defensive back, Tranquill was also in that class. (Perhaps an added wrinkle to adding to the position in the class, it has been one of quick attrition in the recent past. In 2015, Notre Dame signed four linebackers — Bo Wallace never enrolled and Josh Barajas transferred this past summer, leaving only Coney and Bilal.)

The grouping of Jack Lamb, Shayne Simon, Matthew Bauer and Ovie Oghoufo could speak to some doubt of the current freshmen linebackers, Drew White and David Adams. If so, then the Coney’s compatriot query becomes even more convoluted. Could one of the current high school seniors make that jump from the outset? Such seems unlikely.

At that point, turn toward Jonathan Jones, at least for a short-term fix. Or, just to really throw a wrench into these ponderings, perhaps Bilal steps in at a traditional linebacker position and Owusu-Koromoah is counted on in place of or backing up Tranquill at the rover.

This lack of both depth and experience is reminiscent of the state of the Irish defensive line just a few months ago. Expecting such a reclamation again might be asking a bit much of Elko.

This is not to diminish the losses of receiver Miles Boykin and consensus first-team All-American cornerback Julian Love. Notre Dame will miss both of them, Love in particular. But looking at the Irish depth chart, there are avenues to survival without both.

Notre Dame will return two starting receivers in rising senior Chase Claypool and fifth-year-to-be Chris Finke (speaking of which, see below). A number of options exist to replace Love, though obviously none will match his shutdown abilities. Either rising sophomore TaRiq Bracy will put on the necessary muscle to compete with receivers at this level or rising senior Donte Vaughn will return reinvigorated with health after recent surgery to repair a torn labrum surgery or rising sophomore Houston Griffith will move from safety to get his talent on the field or fifth-year Shaun Crawford will recover from an ACL tear quicker than expected or … or … or … If one of those pans out, the Irish defense should be comfortable in its coverage, buoyed by the stalwart safety combination of Alohi Gilman and Jalen Elliott. (Imagine sincerely saying “stalwart safety combination” just six months ago.)

Look again at the depth chart, and such luxuries do not exist at defensive end. If rising seniors Khalid Kareem and Julian Okwara had not opted to return, Notre Dame’s 2019 dreams would have hit a lowered ceiling nine months before the season began. By no means were they certain high-round draft picks, but the allure of athletic and talented defensive ends may have easily led to some outsized draft hopes.

Their backups are certainly more than capable — rising seniors Daelin Hayes and Ade Ogundeji — but a talented second-unit is as important at defensive end as dangerous starters are. To replace the latter with the former is to diminish the entire enterprise outright.

The Irish could not have recovered from losing both Kareem and Okwara, at least not to the extent where Playoff talk would be viable again. Lose one and it would have still been dubious, at best.

Take a look at the teams expected to be in the mix for the Playoff. Using current championship odds … Clemson at 2-to-1, Alabama at just less than 3-to-1, Georgia at 6-to-1, Ohio State at 8-to-1, Michigan at 16-to-1 and then Oklahoma also at 16-to-1. Those first five have been known for their defenses more than anything else in recent years. Bookmakers put some faith in their ability to reload on the fly.

Notre Dame has not earned that trust, and its roster does not indicate it should have. As well as Justin Ademilola performed as a freshman in four games, inserting him into a pivotal role in 2019 would likely be a recipe for a mediocre season. He is another year of development away from being ready for that role, barring a Matt Balis-induced excellent offseason.

The Irish will need Kareem and Okwara to survive the losses of defensive tackles Jerry Tillery and Jonathan Bonner, but if they play as they did in 2018, that is a reasonable ask. If they continue to develop, it becomes a probability more than a Notre Dame leap of faith.

The Irish will miss Boykin’s back-shoulder reliability and everything about Love, but Brian Kelly and his coaching staff coaxed back the two most-pivotal pieces from NFL draft consideration.

Speaking of Finke, he confirmed his intent to return for his final year of eligibility Thursday evening. And he did it in a way only befitting a man comfortable in his own skin.

With the Wednesday announcement of current junior linebacker D.J. Morgan’s intention to transfer this summer as a graduate with two years of eligibility remaining, Notre Dame’s roster drops to 87 scholarship players expected this coming fall. Included among them, at least 12, possibly 14 linebackers. Before explaining that …

Morgan finishes his Irish career with two tackles in two 2017 appearances as a safety. He moved to linebacker during 2018’s spring practices, but never came particularly close to playing time. It remained difficult to see him cracking into the rotation moving forward given the quality of recruiting classes at the position in the last two cycles.

“I would like to thank the University of Notre Dame for everything they have done for me,” Morgan wrote on Twitter. “When I decided to come here, my main goal was to get my degree from this prestigious University, and I am proud to see that I will be completing that goal this summer!

“During this time I will be searching for a new school to attend as a graduate transfer to finish off my last 2 years of eligibility.”

(@deundraymorgan)

Before facing Louisville on Labor Day, the Irish will need to be down to 85 scholarship players. At 87 now, that does not include incoming freshman J.D. Bertrand, who had a recruitment handled in a deliberate fashion so as to make him eligible for an academic scholarship. Notre Dame also continues to chase two defenders — consensus four-star linebacker Asa Turner and consensus four-star defensive end Isaiah Foskey — who could balloon the roster count further.

Lacey will need to be ready for at least four games next season, especially with three of these six returning from injury: Tagovailoa-Amosa with a broken foot, though he did at least take some snaps against Clemson; Franklin from a torn quad that will limit him through the spring; and Spears from a torn ACL that could conceivably cost him 2019.

Former Notre Dame quarterback Brandon Wimbush will continue his career at Central Florida. Wimbush announced his graduate transfer destination Tuesday morning.

“The journey continues on …,” Wimbush wrote on Instagram. “A sincere thank you to Notre Dame for giving me endless opportunities on and off the field. Words truly can not (sic) describe what this incredible University and the PEOPLE mean to me and always will mean to me. I’m truly thankful. Cannot say it enough.

“With that being said, I am excited to announce that UCF has granted me an awesome opportunity to play my last year of collegiate football for their great University.”

Wimbush will enter into a starting opportunity, although an unfortunate one and a competitive one. The late November horrendous knee injury to three-year starter McKenzie Milton will almost-assuredly sideline him through the 2019 season. If not for the injury, Milton would either be starting 2019 for the Knights or headed to the NFL.

In his first year of any action, sophomore Darriel Mack played in 10 games for Central Florida, completing 51 of his 100 pass attempts for 619 yards and three touchdowns, including going 35-of-71 for 526 yards and three scores in the two-plus games Milton missed.

Wimbush finishes his Irish career with a 13-3 record as a starter, including four wins during 2018’s unbeaten regular season. After the Notre Dame offense failed to break 24 points in the first three games of the season, offensive coordinator Chip Long turned to Ian Book for a spark, one Book provided and then some.

Wimbush’s role became non-existent after that, aside from a Senior Day start in place of an injured Book, throwing for 130 yards and three touchdowns while rushing for 68 yards.

Mustipher and Co. will now have reason to keep an eye on the Knights in 2019. After going 25-1 in the last two seasons, Central Florida will want to keep the momentum rolling, particularly with Stanford arriving in Orlando on Sept. 14, a week before the Knights head to Pittsburgh. The Knights genuinely entering the College Football Playoff conversation remains unlikely, but topping those two before rolling through the American Athletic Conference would at least start the discussion, especially if a former Irish quarterback headlines the way.

Named 2018’s Next Man In, Wimbush finishes his Irish career with 2,606 yards on 193-of-382 passing with 20 touchdowns and 12 interceptions along with 1,155 rushing yards and 16 additional touchdowns.

AS FOR NOTRE DAME’S QB IN 2019 …Early Heisman odds came from an online sportsbook Tuesday, betonline.ag. Irish rising senior Ian Book was given 16-to-1 odds, tied for ninth on the listing. Given the names ahead of him, Book’s realistic chances of winning the Heisman Trophy are slim. Only Clemson quarterback Trevor Lawrence and Alabama quarterback Tua Tagovailoa have odds lower than 12-to-1, at 7-to-2 and 4-to-1, respectively.

Then come two Notre Dame opponents — Georgia running back D’Andre Swift and quarterback Jake Fromm, both at 12-to-1. Michigan quarterback Shea Patterson checks in at 25-to-1, just ahead of Stanford quarterback K.J. Costello at 33-to-1.

If nothing else, Book can count on some early-season hype if the Irish top Swift and Fromm on Sept. 21.

Dabo Swinney paid tribute to the late Tyler Trent in his speech while Clemson visited the White House 🙏

A sign of a strong program is one that loses players to the NFL before they exhaust eligibility. In that vein, Notre Dame lost a consensus first-team All-American cornerback, its leading receiver and a long-time tease of a tight end. The last of those (Alizé Mack) was never expected back for a fifth season; replacing Miles Boykin’s production is certainly within reason; and a consensus first-team All-American should be expected to take the route junior Julian Love has.

Even with that expectation, losing Love — and to a lesser extent, Boykin — alters the natural roster cycle, the inherent design intended during recruiting. Reloading is always the hope, the next intention, but very rarely is the young backup comparable to the near professional, even by the end of the coming season.

Nonetheless, the Irish got off easy this cycle compared to four of their 2019 opponents …

GEORGIA: Junior running back Elijah Holyfield, the Bulldogs’ second-leading rusher, departs after gaining 1,018 rushing yards with seven touchdowns on 6.4 yards per carry this season. Frankly, that is the least of Georgia’s losses. Three of quarterback Jake Fromm’s four favorite targets will leave eligibility on the figurative table:

Without running back Karan Higdon, Michigan will presumably rely on its passing game more in 2019, quarterback Shea Patterson’s second season as a Wolverine. (Photo by Gregory Shamus/Getty Images)

MICHIGAN: The Wolverines got good news when quarterback Shea Patterson opted to return for 2019, but losing leading-rusher Karan Higdon (1,178 yards, 10 touchdowns, 5.3 average) will be an issue head coach Jim Harbaugh undoubtedly hoped to avoid. Junior tight end Zach Gentry, Patterson’s third-most prolific target with 32 catches for 514 yards and two scores, will also head to the next level.

On the flip side, Harbaugh could have hoped linebacker Devin Bush (team-leading 80 tackles with 9.5 for loss including five sacks), defensive end Rashan Gary (44 tackles with seven for loss including 3.5 sacks) or linebacker David Long (17 tackles with one interception) might return, but no such luck for Michigan.

Duke junior quarterback Daniel Jones will head to the NFL after his third season as a starter, immediately lowering the Blue Devils’ 2019 expectations. (Photo by Grant Halverson/Getty Images)

DUKE: Junior linebacker Joe Giles-Harris paced the Blue Devils with 81 tackles, including seven for loss with one sack, doing so in only nine games. But losing Giles-Harris is hardly the concern for Duke. The decision to turn pro from quarterback Daniel Jones is.

In his third year as a starter, the junior fought through a broken collarbone to still play in 11 games in 2018, completing 60.5 percent of his passes for 2,674 yards and 22 touchdowns with nine interceptions. He added 319 rushing yards and three touchdowns.

Jones’ decision may come as a surprise, but it is one that should work out well for both him and Notre Dame. Some mock drafts project him as a top-10 pick. In a draft light on quarterbacks — partly because Oregon’s Justin Herbert returned for another season, yet already somewhat counteracted by the Monday draft entry from Oklahoma’s Kyler Murray — Jones could end up being the third or fourth passer picked.

BOSTON COLLEGE: The Eagles will say farewell to junior cornerback Hemp Cheevers after he notched seven interceptions this season, returning one for a touchdown, to go along with 39 tackles.

STANFORD: This will seem like the Cardinal lost a lot to the NFL draft, but it could have been worse: As the departures mounted, so did speculation junior quarterback K.J. Costello might follow them. He opted not to.

Stanford will be without running back Bryce Love after his prodigious two seasons as the starter. Consider that a loss akin to the Irish Love, the inevitable price of enjoying the success in the first place.

Junior receiver J.J. Arcega-Whiteside will capitalize on his breakout season of 1,059 yards and 14 touchdowns, depriving Costello of his favorite jump-ball threat.

Junior tight end Kaden Smith will also head to the next level, in large part thanks to his 47 catches for 635 yards and two touchdowns this past season.

Louisville, New Mexico, Virginia, Bowling Green, USC, Virginia Tech and Navy all did not lose anyone early or pseudo-early to the NFL draft.